1 Measure and mark
Tiling into a corner will invariably mean cutting a tile to size. Don't assume the edge is straight and true; each tile must be measured and cut individually. Remember also to allow for the normal spacing between tiles. If spacers weren't supplied with your tiles, you can use matchsticks or pieces of thick card.
2 Projecting corners
The edges of projecting corners such as around window reveals should be finished with RE (round edge tiles), keeping any cut border tiles to the back of the reveal. REX tiles can be used where two adjacent edges protrude.
3 Feature tiles
Where patterned tiles are used as feature tiles, avoid cutting them. You will need to spend a little more time planning their position at the setting-out stage - especially if you want full-patterned tiles to meet at corners. Interest can also be added by tiling one wall plain in one colour and the other using patterned tiles or tiles in a contrasting colour.